st: xtmelogit model not converging

I am sending this message again. It had the wrong subject heading.
I am running a logistic mixed model and the performing gradient-based optimization iterations are not concave, so the model is not converging. Can you tell me what can be wrong? How can I fix it?
The sample size is 117,894 observations for all variables. The model is specified below.
xi:xtmelogit hoscare i.race i.ses i.agegroup sex i.marry i.cancer_stage i.dxyear_cate i.comorbid || zipcoderesidence: race, intpoints(30) covariance (unstructured) or
Thanks a bunch.
Dale
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